Terrestrial ecosystem carbon dynamics and climate feedbacks

This review article looks at some of the limitations of the traditional method for modelling carbon-cycle climate feedbacks. Carbon-cycle feedbacks are usually dealt with as largely independent above ground (photosynthesis) and below ground (respiration) effects stimulated by a gradual increase in CO2 and temperature.The authors argue that this approach over-simplifies a complex system and consequently neglects dynamic non-linear interactions between physical, chemical and biological processes in the ecosystem.

Some other climatic and environmental factors that might arise out of these dynamic non-linear interactions and modify or even dominate the carbon balance of ecosystems are highlighted. First, the important interacting factors of water and nitrogen, both of which will change under a warmer climate and which will modulate changes in ecosystem processes. Second, the idea that ecosystems do not respond to a mean climate but rather to variabilities and extremes. Third, that the net effect of any environmental change on the carbon balance depends on the reactions of both photosynthesis and respiration, but that below-ground processes in particular are poorly understood, yet are likely to interact in a complex and non-linear way with above-ground processes.

The authors conclude by suggesting that these emerging characteristics might mean that.

Source: Heimann, M. & Reichstein, M. (2008) Terrestrial ecosystem carbon dynamics and climate feedbacks. Nature, 451, 289-292.